Spain is famous for its weather, Benidorm, Spanish food, it's football team, Barcelona, and basically being a rather sunny place overall â none of these descriptions are incorrect, and in fact they are all entirely true!
As the temperature of the air increases its density decreases. Therefore the thrust produced by the engine decreases. As the air pressure increases, its density increases, causing thrust produced by the engine to increase. Altitude has a double effect on thrust. As the altitude increases, the air becomes colder and denser, up to the beginning of stratosphere. This causes the thrust to increase.
The maximum flame temperature increase for burning hydrocarbons (jet fuel) in air is, thus, about 1000Â°C.hen the air is colder (it easily gets -40  degrees up there) and the fuel air mixture is burned, the air  expands alot more than if warm air was entering the engine. On a  warm day a jet will not perform nearly as well as on a cold  day.